A wide variety trailers are known for carrying cargo. For example, van type trailers typically include a deck assembly supported by a side wall structure, wheels and front legs. The deck assembly may include longitudinal floor boards and transverse cross-members, such as I-beams, extending between opposing bottom rails. The deck transfers its load to the bottom rails, wheels, and, depending upon whether or not the trailer is coupled to a tractor or is free-standing, to a tractor fifth wheel or to retractable front legs on the trailer.
In a monocoque type trailer, individual interior side wall panel members and an outer skin are joined together, often by a post, channel or zee-shaped structural member, and to a suspension subframe to form a self-supporting body construction. The outer skin and inner panel members may carry some of the stresses between the posts, floor and roof of the trailer. For example, it is known for the interior panels and the outer skin to attach to a plurality of vertical posts spaced apart along the trailer side wall. Referring to the cross-sectional view of a prior art vertical post shown in FIG. 1, a vertical post 1 includes a longitudinal central section 2 and a pair of first longitudinal flanges 3 disposed on either side of central section 2 and recessed from central section 2 between the central section and an outer skin 4. The outer skin is fastened to a pair of second longitudinal flanges 5 by any suitable means, such as rivets (not shown). Side wall liner panels 6 are attached to the posts at first longitudinal flanges 3 by tapit pins 7, screws or other suitable means.
It is known to include a scuff band along the interior surface of a trailer wall to prevent damage to the wall when cargo is loaded into or removed from the trailer. If provided, the protective scuff band generally protrudes into an otherwise useable storage area within the trailer.
Most side wall liner panels may be generally classified as being either stiff or flexible. Stiff panels, for example made of 0.25xe2x80x3 plywood, resist deflection. Thus, although such a panel may be subject to damage itself, it tends to protect the outer skin from dents from the inside. Flexible panels, for example made of fiber reinforced plastic (xe2x80x9cFRPxe2x80x9d), glass reinforced plastic (xe2x80x9cGRPxe2x80x9d) or other polymer sheet or 0.019-0.027xe2x80x3 steel sheet, deflects easily from interior impacts and tends to snap back into its original condition. It therefore tends to avoid damage, although it may more easily transmit an impact outward to the aluminum outer skin.
A laminate inner panel material sold under the name KEMPLY is formed of a thin, fiber reinforced plastic facer bonded to a thicker, more rigid, plywood substrate, or xe2x80x9cbacker.xe2x80x9d The FRP facer and plywood backer extend over the panel""s entire area, from side to side and top to bottom. The facer and backer end at the same edge at the vertical posts and are attached to the posts directly through the facer and backer.
A panel generically known as xe2x80x9cplymetalxe2x80x9d includes steel and/or aluminum facers bonded to both sides of a thick, e.g. greater than 0.75xe2x80x3, plywood core. Plymetal panels are used for trailer rear doors due to their stiffness, strength and durability.
Composite trailers differ from sheet and post constructions in that composite trailers typically do not have a separate liner panel covering the interior side wall surface. Instead, a single panel defines both the interior and exterior surfaces.
It is known, for example, to form composite panels from FRP or steel facers bonded to both sides of a plywood, plastic or polyurethane foam core. A plurality of adjacent panels attached to each other at their side edges and extending down the trailer""s side forms the side wall. Other constructions are also known, for example trailers having side walls formed of unitary metal or unitary plywood coated on either side with fiberglass and glass.
The present invention recognizes and addresses the foregoing considerations, and others, of prior art construction and methods. Accordingly, it is an object of the present invention to provide an improved trailer.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention.